Otsuka adds new Phase 3 Voyxact data in IgA nephropathy

CURRENT FULL VERSION: Otsuka is extending the Voyxact story with fresh Phase 3 VISIONARY data in IgA nephropathy, this time highlighting exploratory markers beyond proteinuria. At the 2026 ISN World Congress of Nephrology, the company reported that adults treated with Voyxact, or sibeprenlimab-szsi, achieved faster and higher rates of negative microscopic hematuria, adding to the interim Phase 3 evidence that helped the drug win FDA accelerated approval in November 2025. (otsuka-us.com)

That backdrop matters. Voyxact entered the market under the accelerated pathway based on proteinuria reduction, not confirmed long-term kidney protection. In its approval announcement, Otsuka said the drug’s effect on slowing kidney function decline had not yet been established, and that continued approval could depend on confirmatory evidence from the ongoing VISIONARY trial’s 24-month eGFR analysis. FDA’s integrated review framed the unmet need clearly: IgA nephropathy can progress to kidney failure, and despite several newer options, safer therapies that demonstrably slow long-term decline are still needed. (otsuka.co.jp)

The VISIONARY program is one of the largest late-stage IgA nephropathy studies to date. NephJC’s summary of the 2025 interim publication described a global, randomized, placebo-controlled trial across 240 sites in 31 countries, enrolling adults with biopsy-confirmed disease, proteinuria despite optimized supportive care, and eGFR of at least 30 mL/min/1.73 m². In the prespecified interim analysis, sibeprenlimab reduced 24-hour urinary protein-to-creatinine ratio by 51.2% relative to placebo at nine months. By 12 months, proteinuria remained about 57% below baseline, with higher rates of proteinuria remission and hematuria resolution in treated patients. (nephjc.com)

Mechanistically, Voyxact is differentiated as a selective APRIL inhibitor. FDA reviewers noted that APRIL blockade reduces galactose-deficient IgA1, a central pathogenic driver in IgA nephropathy. Otsuka’s March 25, 2026, release said the new WCN analyses reinforce that approach by showing clinically meaningful improvements across key disease markers, not just proteinuria. That’s important because the field has become increasingly crowded with targeted therapies, including sparsentan, iptacopan, targeted-release budesonide, and newer BAFF/APRIL-pathway agents in development. KDIGO’s 2025 guideline update underscores just how fast this category is evolving. (accessdata.fda.gov)

Outside Otsuka, the reaction has been cautiously positive. In ASN’s Kidney Week 2025 press materials, corresponding author Vlado Perkovic said 12-month VISIONARY data suggested sibeprenlimab may have a strong protective effect on kidney function, while also stressing that final confirmation would come from the later readout. NephJC made a similar point more bluntly: proteinuria is a surrogate, not a verdict, and the real test is whether immune modulation changes the disease’s trajectory. Commercially, early physician sentiment appears favorable; Spherix Global Insights reported in February 2026 that 21% of surveyed nephrologists had prescribed Voyxact within two months of approval, with many citing the magnitude of proteinuria reduction and a relatively clean safety profile as reasons for interest. More broadly, Otsuka has also been active on the business-development front: according to PharmaShots, Otsuka America agreed to acquire Transcend Therapeutics for about $1.225 billion, made up of $700 million upfront and roughly $525 million in sales milestones, with closing expected in Q2 2026. The deal would add TSND-201, or methylone, a PTSD program moving into Phase 3 with U.S. patient recruitment underway, plus follow-on prodrug work aimed at improving efficacy, safety, and tolerability. (asn-online.org)

Why it matters: Although this is a human nephrology story, it’s relevant to veterinary professionals because it illustrates where renal therapeutics are heading more broadly: toward mechanism-based, biomarker-informed treatment strategies, and toward regulators accepting surrogate endpoints while awaiting harder outcomes. For clinicians and industry watchers, Voyxact is also a reminder that approval is no longer the end of the evidence story. The more meaningful inflection point may be whether VISIONARY can convert a strong antiproteinuric signal into confirmed preservation of kidney function, which would strengthen Voyxact’s standing against competing IgA nephropathy therapies and likely shape future treatment algorithms. Otsuka’s parallel willingness to commit more than $1 billion to a separate late-stage CNS asset also offers a useful read-through on corporate strategy: this is a company still investing aggressively in specialty innovation rather than simply harvesting recent launches. That last point is an inference based on the regulatory framework, current guideline evolution, the competitive landscape, and recent deal activity. (otsuka.co.jp)

What to watch: The next milestone is the 24-month eGFR analysis from VISIONARY, which Otsuka previously said was expected in early 2026 and is intended to support traditional FDA approval; just as important will be how nephrologists, guideline groups, and payers interpret those data in an increasingly crowded IgA nephropathy market. On the corporate side, the proposed Transcend acquisition is expected to close in Q2 2026, which would bring TSND-201 and its follow-on prodrug program into Otsuka’s pipeline. (otsuka.co.jp)